Climate Change, the Science.

Statistical skill, Bayesian networks have it at a decadal scale, GCM’s don’t.

The climate system as it now stands is a massive collection of known unknowns, data, and unknown unknowns.

Accepting that unknowns can be inferred from the known is not a sin. While the potential exists to chase data down a rabbit hole, on balance it’s better than effective ignorance.

Hellburner -- You (along with several others) were one of the big reasons I left ars. You are still on my ignore list after a very long absence, and I see no reason to change that given posts like this.

Unfortunately you have the extraordinary ability to drop a post like this into the discussion which stops rational discussion in the thread. Those who might dispute you are simply tired of the battle, and perhaps they've all put you on ignore too, but the fact that nobody is willing to just endlessly keep swatting down your repeated dogmatic oracular claims ... we couldn't even do it by tag-team, means you and a few others own this thread and shut it down. I presume that is exactly your goal ... you have succeeded admirably.

Your first statement about "Baysian networks... decadal scale" ... is both unsupported and demonstrably false. I strongly suspect you are conflating efforts such as Cofino et al (Proceedings of the 15th European Conference on Artificial Intelligence, IOS Press, 695 - 700 (2002) about Baysian networks for Probabilistic Weather Prediction into your claim.

In works of this kind please note that the Bayesian network is being applied using the output of a dynamical (physical) weather model as input data, and has been trained using the back history of such model FORECAST outputs AND subsequent observations. By doing this the Baysian network can exhibit further skill over the dynamical model both at interpolating/biasing the resulting forecast to local effects the model does not do right (possibly simply to model resolution, but also potential missing physics), but also possibly improving the forecast's dependence on input data which are persistently biased, or that the resulting "truth" observations are biased!

Any claims about "relative superiority" are nonsense because what is being compared is entirely apples vs. oranges, and the metric of forecasting skills are entirely different, and the normal application of the BN is as a post-hoc band-aid for predictions made from a dynamical model.

Arguing that it is better than the dynamical model these days is idiot, because the fair comparison would be to allow the model to be "tuned" via computation of adjoints ... allowing it the use of the same "error" statistics the Bayesian Network is permitted. (Also in fairness one might allow the model to be run at considerably higher resolution if the goal is to "understand something about reality.")

Your whole truculent claim boils down to "a tuned model usually beats an untuned model." DUH! The point of physical weather and climate models these days is to NOT tune them, or at least to keep all tunings very explicit and understood. In that sense I laud the use of an EXPLICIT statistical post-model to improve local skill ... partitioning the problem into these two sequential steps is honest.

Also, another point, and a current topic of weather/climate modeling computational research ... you see very different model forecast/observation error behaviors for two different scenarios: using the raw observations, or using a dynamical reanalysis. The forecasts usually look a lot better compared to the reanalysis.

This is the whole dynamical 4DVAR problem writ large. To the extent the model's resolution while doing the reanalysis is adequate (and for the purposes of research we can generally afford the computation to make it so, for a limited number of cases anyway) what this is demonstrating is that either the "truth" data are dynamically inconsistent, or the fundamental dynamics in the model are wrong. Particularly when we are looking at relatively short term weather prediction (24 hours or less), the physics in the good models is reasonably complete ... it's a data and resolution problem. If one looks at the residuals of the forecast vs the reanalysis there is far less "to play with" for any statistical model ... and so it is throwing everything back on the real problem -- your input data and 4DVAR.

4DVAR ... is a bitch. A big part of the problem is that the models are non-linear, and adjoints are a bitch, and generally approximate at best, if not fair to disparage as "little better than ad hoc." This is a current topic of math/numerical research.

For longer-term predictions (out to climate) I agree that it is less clear that relevant physics in the models is entirely adequate (oceans, ice, bio/ecological-feedbacks into albedo and atmospheric composition, etc). Claiming that BN solves this is nuts though, because there simply has not been enough forecast with SUBSEQUENT Baysian reanalysis to demonstrate anything at all. In a few hundred years there might be ... you and I will not be around to 'discuss' this.

Your other two claims are nothing more than otiose pontification. Nobody made you the pope, or the oracle of Delphi.

Could you at least go back to your era of Coccolithophore enthusiasms? It's not prima-facie irrational to posit the new wonderful negative feedback mechanism du jour which will result in a very low climate sensitivity, so we can continue burning fossil fuels without concern as far as large climate effects (of course ocean acidification is another inconvenient issue, eh?). Your only problem with such theses is to explain why it works now and didn't work in the recorded geohistory.

In particular you need to explain how the Milankovitch amplification was possible, but this new automagical feedback you posit didn't interfere with that. One can immediately see ways this might be possible, one can imagine simply that this new mechanism only kicks in when it is hot, e.g. Your problem then is to explain the Eemian, or the PETM. Good luck, particularly with new glaciology results which appear to demonstrate that the Eemian was 6-8 C hotter in the middle of Greenland than today!

Much more damming is that Bayesian models are very sensitive to departures from assumptions, unlike regression, which is in the middle for sensitivity, or other forms of estimation. The intellectual "cleanliness" of Bayesian models belies their inaccuracy, and may mislead some practitioners. I'm arguing that a Bayesian model can be a dumber form of regression fitting.

I don't have access to the paper being discussed (if I even have the right one), but I'm a bit curious what you mean here when you say that Bayesian models are more sensitive than other techniques to departures from assumptions. I'm having trouble thinking of a context in which that might be true, unless you are perhaps trying to reference some very specific technique here. For example, "Bayesian" and "regression" aren't orthogonal terms in any sense I'm aware of (and of course, there are plenty of ways to relax model assumptions - even ignoring the entire field of Bayesian nonparametrics). I'm not trying to be argumentative - I'm just trying to understand the context of your statement better.

OperaMalensky ... in general I am "with you" on this one. The Bayesian vs Frequentist wars are one I don't want to reenter in a climate thread .. or for that matter probably on Ars at all. Also, there are SO many variations of assumption in "Bayesian Regression" that one really can't say much of anything in generalities, one must look very carefully at the particular formulation/assumption.

And then there's the fact of the matter that if the "priors" actually do exhibit gaussian variances then the conventional Bayesian regression becomes indentically Least-Squares ... boring indeed.

There is of course the horribly sophomoric mistake of using Bayesian regressions where the priors have limited sample statistics so one gets a censored result ... but this isn't very much different than applying a Langrangian constraint (effectively a constraint against an assumed climatology) ... the only real difference in the outcome will be a difference in the computed statistical uncertainties.

In almost all regression/fitting problems the real issue isn't the regression/fit, it's the estimate of the uncertainty, or put another way, in any particular result in use, how much of the information comes from the observations, and how much from the constraints (priors, or "climatology.")

My big bitch with an enormous fraction of statistical papers in general is that either their claims for their error bars are outright bosh, or the details of understanding what they really are is so difficult and opaque ... we just don't really know. Uncertainty estimation given sampled priors .... is a bitch to justify rigorously.

Folks ... my daughter is a senior in HS this year, and she's been a serious skier since she was a toddler. She's not ski-racer material, but definitely ski-patrol. Most of my family lives out west and we go skiing out there every Feb, will head out soon.

What does this have to do with climate? In Albany NY this afternoon it was 54 F at 3 PM. I got a call from my daughter -- ski-bus was canceled, where she goes to ski is closing, all the snow is gone. It's one of the tallest places other than going up into Vermont or Gore/Lake Placid. And they are in big trouble right now too.

Ski areas in the North East depend on making snow. Some of the bigger places will spend millions of dollars in a season making it. It's almost all gone right now, everywhere except the higher parts of the higher peaks, farther north. It's going to be a financial disaster to a lot of ski areas ... a bad, bad year.

Warm spells at the end of January or early February are statistically fairly common around here, that's not new. But what is new is that the last decade has seen very sharply warmer winters, so evident that everyone knows it. And the warm spells come in and they stay and the snow all melts away. Bare is normal now in the valleys, for much of the winter. Snow comes, it cannot be depended upon to last.

Is this, by itself, "evidence of climate change?" No it isn't ... not by itself. It might be passed off as a regional scale decadal or even multi-decadal anomaly, if there weren't other evidences.

But the basic premise of CO2-driven AGW is that it warms more at night than during the day, it warms more at high latitudes than low, it warms more during winter than during summer. All of these stem from two simple simple facts: the first is that under the stated conditions H2O amplification is less important ... the raw CO2 effect by itself becomes more dominant. The second is that under these conditions convective heat fluxes don't drive the heat transfer so much.

Winter has come to the vast, northernmost reaches of Canada, the sparsely populated area surrounding the Arctic Circle historically characterized by severely cold weather. But these days refrigeration systems are needed to keep the ice cold at hockey arenas.

It has been too warm for December hockey in the Arctic, the latest sign that climate change is altering the environment and the way people live — especially in the far north, where the effects of rising temperatures are most pronounced.

Nine of the 14 villages in Nunavik, a region in northernmost Quebec, have installed cooling systems at community arenas within the last five years.

In Canada’s Nunavut Territory, towns including Arviat, Igloolik, Sanikiluaq and Repulse Bay have resorted to cooling systems. A system is also being installed at the community arena in Cape Dorset, a hamlet of 1,400 just 150 miles south of the Arctic Circle.

.....

The warming trend has been especially noticeable in the Canadian Arctic.

In Cape Dorset, Hayward noted, it rained on Christmas Day in 2010. Last month, on the first day of winter, it was only about 27 degrees.

“There’s been a big change over the past few years, to the point where without these systems now, it would not be possible for the villages to make their ice inside the arenas,” said Joe Juneau, a former N.H.L. player who has run a youth hockey program in Nunavik since 2006.

“When I started the program, I remember some of the villages starting building their ice in early November,” said Juneau, who holds an aeronautical engineering degree from Rensselaer Polytechnic Institute. “Now it’s very problematic. Without these systems, it would not be possible anymore for communities to have natural ice in their arenas.”

Think about that. Inuit and Inupiat communities cannot have dependable ice at the arctic circle, in early December. Also bye the bye, RPI is right across the Hudson from me and sometimes I go over there to hear seminars, once in a rare while give one.

I moved to Albany in '89 from the west coast, when I got the appointment here. It was a huge change for me, cultural, academic ... on it goes. I'm not too far from the end of my career now ... hope to be able to carry on till my daughter's through college, but that may not happen. I'm doing hurricane stuff now ... all the research money for fundamental climate-related atmospheric measurements has largely dried up, and most folks have moved on. A significant part of the loss of funding is that NASA and DOE have been the agencies which have funded the bulk of the fundamental work, and both are on the ropes for similar reasons and shifting money out of these areas (toward sustaining things like "the senate launch system"), but also it's rational. It's time. The big "questions" are all answered to the point where nobody but the idiots argue. Many damned relevant "lesser" questions remain; the science of the earth's climate is hardly complete. But the big f**king policy question is answered beyond all rational criticism: it's CO2 stupid (and to a lesser extent methane).

The politicians don;t need to fund more research, and such research won't really have any impact on policy decisions either.

I've lived to see it ,,, still have a bunch of years to live unless I am unlucky. But when I moved to Albany in '89 feet of snow on the ground all winter was normal. I remember digging snow out from around the windows of my house one really bad year. And the people who live farther north have experienced it even more extremely.

And my daughter ... who I still think of as the 40-lb string bean who was just learning to parallel .. but now in truth I don't chase her around, she's too fast and I'm too old and I don't want to get seriously hurt. But we both learned to east-coast-ski together. And that means skiing ice ... we go out west and we can't ski powder for sh*t, don't even have the skis or the technique. But nobody out there in my family skis ice like either one of us does, particularly Joan.

And now even all that ice and manmade snow-cone is going away. She's planning to move out west and north when she's out of college. I understand why.

And anyone who sees this who's a New Yorker ... thanks folks. I've had a great career at a NY state school, appreciate it a lot. but there's no mountain on the east coast that reaches 2 km ... and winter sports are going to disappear here. And the mountains in eastern Canada are even more pathetic jokes ... the glaciers ate them up and crushed them down.

And anyone who sees this who's a New Yorker ... thanks folks. I've had a great career at a NY state school, appreciate it a lot. but there's no mountain on the east coast that reaches 2 km ... and winter sports are going to disappear here. And the mountains in eastern Canada are even more pathetic jokes ... the glaciers ate them up and crushed them down.

I've also heard about BC being able to grow oranges, even though this was previously impossible due to a cooler climate.

In Norway, there's a glacier near Olden at the east end of Nordfjord. Because of problems like rock slides, you can only get so close (still a mile at least from the main action) without some kind of permit.

But, you can get close enough to see a smallish-lake being fed (this was in May where it was still serious Winter and deep snow in the upper elevations) and you could also see glacial snow melt.

There's no doubt when you're seeing a glacier. It has a definite aquamarine cast that regular ice doesn't have. It's not something that seems to be widely written about, oddly enough, but once you see it, you know. It's not subtle.

Near the chalet at the start of our hike was a sign that said, basically, "the glacier stopped here around 1800". We walked several miles to the aforementioned point where we could stop.

The run-off would not be entirely glacial, but a lot of it had to be. The smallish lake (all melt water it seemed to me) fed a small stream. The water came by in a positive torrent. And, as I pointed out, we walked quite a ways from the 1800's marker.

The locals were talking seriously of the day when the glacier will go away and they can reach communities in maybe half an hour that now takes about four . . . because you have to (as I did) drive around the glacier.

Meanwhile, in my various trips to the Caribbean, from east to west, more than one diving operator admitted that the sea changes (either temperature or acidity, take your pick, these guys weren't scientists) were killing off coral. Coral always dies, of course, but there's a lot more bleached, dead coral every year. It's not something they probably would like to admit to (would you admit your basic rationale for your business was dying before your eyes?) but there are a lot of honest operators who will tell you the truth about it.

There is enough going on in my lifetime (I'm of similar age to BA) that if you work at it only a little, you can find evidence of it happening.

This reminds me a little of the arguments about air and water pollution in the '60s. Industry tried to deny that, too, but people caught on when (for instance) you couldn't find a beach on Lake Erie that the authorities said was safe for swimming. When you're a kid, it's memorable to take a drive from Southern Ohio up to Erie just for the swim and then to go wandering from beach to beach with no joy.

I think the above few posts, should be taken with a grain of salt, thanks to confirmation bias (in this case, I think we would be more likely to notice evidence of warming, rather than that of cooling). That being said, the reality is that there is a lot of unbiased statistical, modeled, and measured evidence which corresponds with the personal experiences mentioned, which is what makes them worrying.

Personally, over the last 7 years, I have been in the midst of 2 "once in a lifetime, never seen before" flooding events in 2 major cities. Which brings me to the question if how many once in a lifetime events does it take to realize that they really aren't once in a lifetime anymore?

But, in neither case did I run off looking for the evidence I cited. Moreover, in many cases, I didn't ask the operators in the Caribbean, it came up on conversation with others. And, I've been to at least half a dozen distinct places and multiple trips to Bonaire and Belize, which are pretty extensive in terms of coral.

I was on vacation, not looking for Observatory fodder. It's just something I ran into. I had no idea that I was going to run into either one before I did. How could I? I'd been to neither place before these conversations came up.

I don't know of any significant counter-examples; maybe I just don't go to the right places, but you would think that visiting Norway in early May might have produced one instead of the converse. It's just that none of the locals were saying anything "useful" to the anti side of it, as it happens.

I don't want anyone to think that I was advocating an anecdote of a single episode as any sort of "proof" of a global process. I told it as an (I hope) interesting personal story oddly connected to my life as a scientist.

I'm not even going to bother getting data for the northeast and working it up and arguing about statistical significance and so on ... sort of see that as a mediocre MS thesis, probably publishable but at this point, if that's all one gets out of it, totally ho-hum these days ... unless one is a grad student needing a tee-ball thesis topic.

The wider point is borne out by the data analysis and reporting done "by the usual suspects" ... the same folks who gather the global mean temperature records also produce other areal aggregations, show trends vs latitude etc. And this does bring up a point which I think is worth trying to bring to wider attention, goes like this:

Many years ago when I was a young scientist I went to a meeting and mostly sat in the corner and kept my mouth shut where one of the topics was exactly "what metric of global warming shall we track and report?" Jim Hansen was a vigorous proponent that it must be the global (areal) mean temperature. There were many arguments back then against this -- I will get to those -- and there's only one argument for it, the argument Jim made: the political argument that it was the only metric which "everyone would understand" (hah!) and everyone would accept as applying to them. And it carried the day.

The areal-weighted global mean temperature is a lousy and difficult indicator of CO2-driven climate change. Obviously it's dominated by the tropics and mostly dominated by the great Pacific ocean, and for starters, there's damn little data taken out there now, less data back then, and data reliability has always been a PITA. But beyond that the basic physics says that we do NOT expect the tropics to warm as rapidly, and so we are producing an aggregated measurand where the largest contribution comes from measurements taken were we expect the signal we are looking for to be weakest, and were other processes (notably ENSOs) add lots of variance.

Folks back then weren't stupid, and there were vigorous advocates for other weightings or schemes and I won't go into any of that because it doesn't matter. I do wonder though what the decision would have been if the folks debating that political decision had realized the depths of the Denialism that they would end up facing. The community then very clearly understood that it would take more time to demonstrate an unambiguous statistical signal of CO2-driven AGW in the global mean temperature, as opposed to trends at high latitude, or several other metrics. The community felt that for communication purposes and precisely to get the IPCC process started, it was necessary to promote the global mean temperature.

What this fast-forwards to today is that most of the scientists working in the field see the hockey-stick wars as having degenerated into a farce, not just because of the Denialism and the wacky arguments, but because the global mean temperature simply isn't all that useful, really. And if you are interested in assessing impacts it radically understates them in the near term, because most of the impacts are coming from high-latitude processes and the numbers that represent these are the high-latitude warming rates and if you care the high-latitude "CO2 sensitivity coefficients" ... and these are much bigger numbers, and also if you go looking at those trends ... how shall I say it ... you've got to be beyond a fool to try to argue them?

To a scientist it's those trends which are the relevant detector of the CO2 warming ... world-of-duh if you want to detect something you measure where the expected signal of the process you are trying to measure is strongest, and the interferences weakest.

But ... sigh ... global mean temperatures it is ... to the public anyway.

And at the moment we do have a burp in the global mean trends and so we've got maximum opportunity for obfuscation -- you see it everywhere. And the question of just exactly WHY we have the burp is interesting. The obvious contenders are some combination of enormous increases in aerosols from Asia, and potential "funny business" with heat transport into the oceans. But again it is clear that most of this burp is tropical oceans -- the high latitude trends are sailing on un-burped.

I expect that a fair amount of this will get sorted out within the next few years ... but we do have data problems ... Trenberth's "it's a travesty" properly understood. The US is starting to disinvest in good climate data though.

..."what metric of global warming shall we track and report?" Jim Hansen was a vigorous proponent that it must be the global (areal) mean temperature...

The areal-weighted global mean temperature is a lousy and difficult indicator of CO2-driven climate change. Obviously it's dominated by the tropics and mostly dominated by the great Pacific ocean, and for starters, there's damn little data taken out there now, less data back then, and data reliability has always been a PITA. But beyond that the basic physics says that we do NOT expect the tropics to warm as rapidly, and so we are producing an aggregated measurand where the largest contribution comes from measurements taken were we expect the signal we are looking for to be weakest, and were other processes (notably ENSOs) add lots of variance.

There's some recent published work which suggests that it is exactly in the tropics where the S/N ratio of warming will first become "significant" (i.e., outside of variability):

But, in neither case did I run off looking for the evidence I cited. Moreover, in many cases, I didn't ask the operators in the Caribbean, it came up on conversation with others. And, I've been to at least half a dozen distinct places and multiple trips to Bonaire and Belize, which are pretty extensive in terms of coral.

I was on vacation, not looking for Observatory fodder. It's just something I ran into. I had no idea that I was going to run into either one before I did. How could I? I'd been to neither place before these conversations came up.

I don't know of any significant counter-examples; maybe I just don't go to the right places, but you would think that visiting Norway in early May might have produced one instead of the converse. It's just that none of the locals were saying anything "useful" to the anti side of it, as it happens.

Coral has only been observed continuously since the second world war. The various diseases and swings of population level typically are first ascribed to the environmental change du jour before serious diagnosis is pursued. In the case of coral that would be changes in water temperature and water pollution. That holds true also of a lot of processes that occur on land. An example is the white nose disease of bats. Now, it may still be that "climate change" was the big factor leading to the white nose disease and the inciting fungus had always been around, but it is highly unlikely. Yet climate change was the first factor put forward in the popular press.

Each SPECIES of coral could support a COMMUNITY of scientists studying various aspects of its life. We're lucky to have 100 or 1000 scientists in the world studying all species of coral. There's a huge amount that is not known.

Well, that's an interesting article wrt the statistics of detection and for the discussion at hand its reference list alone is useful, but I am mystified that they ignore the arctic as a possible "region" ... and there seems to be some implicit criterion of "region" which is never explained.

Well, ironically Hurricanes are my gig these days ... though I've rather jumped into it and can hardly be considered an expert on anything except some narrow technical issues of what we are working on.

But Sandy was a wimp of a hurricane, barely a Cat 1 when it got to NY and NJ. Almost all the damage Sandy produced was storm surge. It was an unusually large hurricane though (in diameter), and its size was influenced by merging with a propagating trough which was a bit unusual ... the two events concurring having even lower odds.

Also we did have a relative hurricane lull from roughly WWII to about the 70s associated with the NAO, and now we are in the other phase. I don't know whether it is settled that the NAO oscillation reduced the frequency of hurricanes staying far enough west to be a problem to the Northeast ... I don't think that claim has been settled one way or another (might be wrong about that). In any event, this particular NAO was a mild time for the NE US.

But still .... there are decent data for the occurrence of hurricanes in the NE over the last 2000 years or so from stream cores (the deposits show extreme flood events and cores taken at selected stream inlets show big surge events nicely too) ... I can't find the relevant paper but I remember hearing it discussed at a meeting ... my google fu isn't up to it. Neither Sandy nor Irene were really so unusual, seen against that statistical record.

The claims of the folks creating the flood maps about "100 year storm" frequencies have always been mother's dirty little secret, they've ALWAYS underestimated the frequency and severity of fairly common storms. They've always been biased in favor of the building and real-estate interests, anyone suggesting less favorable statistics has been shouted down as "alarmist" and "anti-growth."

In any epoch of 100 years, you can find considerably more than 1 "100 year events" in almost every quoted statistic of this type. It ought to be embarrassing, but it rarely gets attention.

Some of this is due to "the black swan" phenomenon ... that the people making the predictions are extrapolating a frequency distribution integral from some first mode of a distribution (itself a very dangerous thing to do), and not recognizing that there is another small mode out there, due to different physics or circumstances.

But frankly, a lot of it is just the pressures of boosterism and not "standing in the way of progress."

Hurricane Sandy cleaned out a lot of stupid development. People who build on barrier islands really have no excuse for thinking that they are doing anything other than the literal "house built on sand" ... in the way of severe storms. Building on filled land in and around New York harbor is hardly smarter.

The available evidence we have does suggest that hurricanes are likely to become somewhat stronger as a result of AGW, and even more interesting that hurricanes may be seen more frequently in areas where they are now exceedingly rare (the Mediterranean is a possibility, the Red and Caspian seas possibly too), but the frequencies aren't so likely to increase in the areas where they are now reasonably common. These predictions all come from the work of Kerry Emmanuel, who is certainly not a gaga "warmist."

Katrina was the worst disaster in American history, and New Orleans was just sitting there to take it, but at least it was a Cat 5. 2005 was a BAD hurricane year though, there were two other serious hurricanes which it the US which few remember ... but would be remembered if it weren't for Katrina.

Coral has only been observed continuously since the second world war. The various diseases and swings of population level typically are first ascribed to the environmental change du jour before serious diagnosis is pursued. In the case of coral that would be changes in water temperature and water pollution. That holds true also of a lot of processes that occur on land. An example is the white nose disease of bats. Now, it may still be that "climate change" was the big factor leading to the white nose disease and the inciting fungus had always been around, but it is highly unlikely. Yet climate change was the first factor put forward in the popular press.

Each SPECIES of coral could support a COMMUNITY of scientists studying various aspects of its life. We're lucky to have 100 or 1000 scientists in the world studying all species of coral. There's a huge amount that is not known.

All true enough ... but corals don't do well as the water acidifies, for obvious reasons. And the geological history shows ecological successions of corals vs Bryozoans, nearly identically correlated with the CO2 partial pressure and ocean pH ... assuming you've got a few million years for evolution to do its work.

Almost any species under stress becomes more vulnerable to parasites and predators. And whether or not the current pH (or temperatures) are the cause right now ... if the CO2 partial pressure keeps going up, most of the corals will be doomed. The lab experiments show this. (Also, very few home aquarists keep living corals because they are tough to keep, but those who do, damned easy to kill off simply from the CO2 partial pressure in the home getting too high and overwhelming whatever pH stabilization is set up)

Each SPECIES of coral could support a COMMUNITY of scientists studying various aspects of its life. We're lucky to have 100 or 1000 scientists in the world studying all species of coral. There's a huge amount that is not known.

Point taken, but whatever is going on, it seems to be widespread. The places I go in the Caribbean where this has been observed, the wipe outs are pretty widespread. You see healthy coral, nearly universal white, healthy again, and so on, as you snorkel by.

Admittedly I didn't do any survey, nor have I the skills anyway, but I don't recall detecting any particular species or sets of species making new footholds in the devastated areas (there were some, now and then, to be sure).

All I know is that the locals tell me it has increased over time (and all over the whole Caribbean) and it does not seem to discriminate between species where certain ones are wiped out and the others survive. Kind of like temperature and/or acidity is going up in a lot of places. Or salinity maybe. It has to be something that can happen everywhere, because the complaints are everywhere I go. So, global warming would be where I would put my chips.

Whatever the actual cause, it isn't some local or species-specific effect.

I've kinda done the delayed double-take on this, which is perhaps Kalessin's original point ... that the model results from which they derive their claim do show strong dT/dt in regions of the Western Tropical Pacific ... and I don't know why.

I presume this must be some ocean physics/current phenomenon. I am trying to think of who I know who could answer this one ... will see what I can find. But it's not my high priority this coming week, and the week after my daughter and I head west ... for some non-ice skiing.

Each SPECIES of coral could support a COMMUNITY of scientists studying various aspects of its life. We're lucky to have 100 or 1000 scientists in the world studying all species of coral. There's a huge amount that is not known.

Point taken, but whatever is going on, it seems to be widespread. The places I go in the Caribbean where this has been observed, the wipe outs are pretty widespread. You see healthy coral, nearly universal white, healthy again, and so on, as you snorkel by.

Admittedly I didn't do any survey, nor have I the skills anyway, but I don't recall detecting any particular species or sets of species making new footholds in the devastated areas (there were some, now and then, to be sure).

All I know is that the locals tell me it has increased over time (and all over the whole Caribbean) and it does not seem to discriminate between species where certain ones are wiped out and the others survive. Kind of like temperature and/or acidity is going up in a lot of places. Or salinity maybe. It has to be something that can happen everywhere, because the complaints are everywhere I go. So, global warming would be where I would put my chips.

Whatever the actual cause, it isn't some local or species-specific effect.

These are anecdotes. What is your evidence for this? Without knowing what species you are observing, and without sustained surveys, little can be inferred. Diseases of corals are only now being identified; many reefs remain quite healthy. Yes, if the ocean drops to pH 7 or whatever, the corals will die. Right now, it will take careful observation and experimentation to determine causes of mortality. Then you might be able to detect pan-specific, widespread mortality and unambiguously assign causes.

The reviews are complete and it has been accepted, I was NOT a reviewer, nor an author. The reading draft was circulating quite freely among the aerosol climate-science crowd, no surprise given the Uncle Tom Cobbley and all author list.

This paper is really just a big meta-survey of the existing literature on black-carbon aerosol effects (and authors), and it's obviously intended to make the next IPCC and is part of that general effort. Its central conclusions are that the best estimate global-average 'Atmospheric Aerosol Optical Depth owing to black carbon [AAOD(bc)] = 0.0065, with upper and lower 2-sigma bounds of 0.0074 and 0.0034. Direct Radiative Forcing [DRF] = 0.2 - 0.9 W/m^2 (moderate heating). Indirect cloud effects are estimated to be roughly 1.1 W/m^2 but with uncertainties that exceed the value, thus the overall result allows some chance of slight cooling,

Note that this does not include deposited BC effects on glaciers, the arctic etc.

The results roughly double the previous IPCC consensus, but don't really change the global climate assessment all that much. I don't have any strong reaction to this paper one way or the other (there's nothing particularly new in it). I won't/wouldn't post comments or criticisms here until after it is in print in any event.

Phase transitions of atmospheric water play a ubiquitous role in the Earth’s climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release

...

We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

The devil in the details may well help resolve why atmospheric water vapor has not been tracking up with rising temperature and the subsequent wrench in climate sensitivity determinations.

These are anecdotes. What is your evidence for this? Without knowing what species you are observing, and without sustained surveys, little can be inferred. Diseases of corals are only now being identified; many reefs remain quite healthy. Yes, if the ocean drops to pH 7 or whatever, the corals will die. Right now, it will take careful observation and experimentation to determine causes of mortality. Then you might be able to detect pan-specific, widespread mortality and unambiguously assign causes.

Coral reefs around the world are all in catastrophic decline. Overfishing has removed key species from the ecosystems, while other species (such as jellyfish) have proliferated. Rising acidification and a decline in plankton populations is accelerating everywhere. Acidification combined with rising temperatures means that the vast majority of coral reefs will be quite dead in as little as 50 years, many of which will be wiped out long before then. There is a reason for the large expansion in industrial fish farming. Wild fish simply aren't out there any more.

If anyone has a desire to see coral reefs, better see them now. Incidentally, the corals in the Red Sea are still quite fantastic.

“Worse than we thought” has been one of the most durable phrases lately among those pushing for urgent action to stem the buildup of greenhouse gases linked to global warming.

But on one critically important metric — how hot the planet will get from a doubling of the pre-industrial concentration of greenhouse gases, a k a “climate sensitivity” — some climate researchers with substantial publication records are shifting toward the lower end of the warming spectrum.

There’s still plenty of global warming and centuries of coastal retreats in the pipeline, so this is hardly a “benign” situation, as some have cast it.

But while plenty of other climate scientists hold firm to the idea that the full range of possible outcomes, including a disruptively dangerous warming of more than 4.5 degrees C. (8 degrees F.), remain in play, it’s getting harder to see why the high-end projections are given much weight.

The scientific bits are not very surprising, and some posters have been discussing some or all of the main points here and elsewhere at Ars for some years now (often drawing fairly hostile responses). However, I think the example comments by James Annan, as they have evolved over the years, and some of the replies make for pretty interesting reading about the "sociology" of science. (See especially the reply by Gavin Schmidt of ReaClimate.org).

These are anecdotes. What is your evidence for this? Without knowing what species you are observing, and without sustained surveys, little can be inferred. Diseases of corals are only now being identified; many reefs remain quite healthy. Yes, if the ocean drops to pH 7 or whatever, the corals will die. Right now, it will take careful observation and experimentation to determine causes of mortality. Then you might be able to detect pan-specific, widespread mortality and unambiguously assign causes.

Coral reefs around the world are all in catastrophic decline. Overfishing has removed key species from the ecosystems, while other species (such as jellyfish) have proliferated. Rising acidification and a decline in plankton populations is accelerating everywhere. Acidification combined with rising temperatures means that the vast majority of coral reefs will be quite dead in as little as 50 years, many of which will be wiped out long before then. There is a reason for the large expansion in industrial fish farming. Wild fish simply aren't out there any more.

If anyone has a desire to see coral reefs, better see them now. Incidentally, the corals in the Red Sea are still quite fantastic.

Phase transitions of atmospheric water play a ubiquitous role in the Earth’s climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release

...

We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.

The devil in the details may well help resolve why atmospheric water vapor has not been tracking up with rising temperature and the subsequent wrench in climate sensitivity determinations.

Since any non-comically false climate model uses the Navier-Stokes Equations, I do not see the merit of the paper. The Navier-Stokes Equations are Mass as well as Momentum conservative, meaning that any momentum changing effects (=force to drive winds) described there will be covered directly by the equation system. One only needs the rates of condensation and evaporation, and the Navier-Stokes equations will "magically" handle all effects. For the rates of condensation and evaporation one needs an energy equation. And this is where the difficulty lies, but it is not the subject of the paper...

Further difficulties arrive once one starts to have multi-phase fluids (liquid + gas, or even worse for clouds liquid + solid + gas). Then throw in some nice turbulence to make that even more difficult. But water vapour condensation? Easy and automatically solved by the Navier-Stokes Equations.

Since any non-comically false climate model uses the Navier-Stokes Equations, I do not see the merit of the paper...Further difficulties arrive once one starts to have multi-phase fluids (liquid + gas, or even worse for clouds liquid + solid + gas). Then throw in some nice turbulence to make that even more difficult. But water vapour condensation? Easy and automatically solved by the Navier-Stokes Equations.

Isn't water condensate + vapor a two-phase fluid?

Also, the paper specifically mentions the combination of both thermodynamic and radiative effects of water condensation. Where in the N-S equations are radiative effects "solved"?

While we're talking about apoplexy, why don't we discuss some of the recent exchanges on climate sensitivity:

A recent post by Andy Revkin at NYTimes Dot Earth has elicited a reasonable collection of comments. The article begins: .....

Honestly I am mystified that Revkin wrote that thing, or at least that choosing to do so, he starts out with "LOW..."

Basically he's saying he thinks that the CO2 climate sensitivity is about 3 C/doubling. That's right smack in the middle of the IPCC consensus. Wow, that's a yawn. That's NOT "LOW" by any one's appreciation ... numbers like 1 C/doubling are "low."

If what he is saying is that he thinks numbers over say 4 C/doubling are "unreasonable" that's what he ought to say, but in fact he offers nothing new on those topics ... just relays a variety of other opinions, few directly from published reviewed work.

Lord, it has brought out all the crazies. An unsympathetic person might conclude that Andy needed to bump his readership stats. I read through the post and most of the comments ... IMO the comments are a waste of time, unless you like to read stuff from people who call themselves things like "Al Gore," "Inspector Clouseau" ... on it goes ... all ranting strange stuff.

Lord, it has brought out all the crazies. An unsympathetic person might conclude that Andy needed to bump his readership stats. I read through the post and most of the comments ... IMO the comments are a waste of time, unless you like to read stuff from people who call themselves things like "Al Gore," "Inspector Clouseau" ... on it goes ... all ranting strange stuff.

More interesting were the comments by "known figures," e.g., Annan, Connolley, Schmidt, Betts, (Romm ?). Not so sure about Inspector Clouseau...

Since any non-comically false climate model uses the Navier-Stokes Equations, I do not see the merit of the paper...Further difficulties arrive once one starts to have multi-phase fluids (liquid + gas, or even worse for clouds liquid + solid + gas). Then throw in some nice turbulence to make that even more difficult. But water vapour condensation? Easy and automatically solved by the Navier-Stokes Equations.

Isn't water condensate + vapor a two-phase fluid?

Also, the paper specifically mentions the combination of both thermodynamic and radiative effects of water condensation. Where in the N-S equations are radiative effects "solved"?

The Navier-Stokes equations do not deal with phase transitions explicitly at all. It's basically just conservation of momentum in a fluid. See here, but Kalessin's comments suggest he's already seen this:

In this wiki article, the real essence of the N-S equation, both physics and limitations, comes from the discussion of "stresses"

You cannot solve them usefully without ancillary equation(s), an absolute necessity is an equation of state. One can create equations of state which will permit two-phase flows ... but there are very real limitations if the scale of the condensed phase becomes close to the "inner scale" of the turbulence. This is not really a problem for planetary atmosphere applications.

Radiation terms do not directly affect momentum (nobody is worried about the momentum transfer of a photon being aborbed or scattered), they are just adding heat which works via the equation(s) of state. (Changes density, produces buoyancy)

I've lost track of progress in the area, but the last full-physics N-S simulation I saw reported solved the dynamics of a flow at about a Re = 1e7 over a flat plate about a meter square with a simulated time of a few minutes ... and that was a big supercomputing effort ... a decade ago. Obviously they could do much more than that now, but I haven't seen it. If it's being done they aren't learning anything earth-shaking from it for their troubles.

Almost all hydrodynamic models solve systems of the Euler equations, with some sort of boogered turbulence/boundary layer "closure scheme" ... of which there are many. Weather and Climate models do this.